v0.2.3

This release provides stabilization fixes as follow-up changes to 0.2.2:

• Fixes race that caused double-deletion of HCM active streams crashing (#669)
• Fixes DNS resolution when starting Envoy Mobile offline on iOS (#672)
• Fixes for API listener crashes (#667 and #674)
• Fixes for linking and assertions (#663)
• Fixes bad access in ~DnsCache() in Envoy upstream (#690)
• Fixes bug in Dynamic Forward Proxy Cluster in Envoy Upstream (#678)
• Adds known issue assertion that prevents crash on force-close (#699)

Additional changes:

• Allows zero for upstream timeout specification (#659)
• Adds process logging for Android (#684)
• Adds the ability to decide upstream protocol for requests (#697)